问题如下图：
选项：
A. 
B. 
C. 
解释：这里是通过反向操作获利吗？为什么CDS的标的不同呢，一个是投资级一个是投机级，我能够理解，当Italy经济变差时，信用风险会变大，CDS的buyer会获利，但是为什么要一买一卖？
NO.PZ201712110200000507 问题如下 Baseon the three economic outlook statements, a profitable long/short tra woulto: A.sell protection using a CanaC IG anbuy protection using a US C IG. B.buy protection using iTraxx Crossover ansell protection using iTraxx Main. C.buy protection using electric cC ansell protection using a trationcC. B is correct.Baseon Outlook 1, ChanSmith anticipate thEurope’s economy will weaken. In orr to profit from this forecast, one woulbuy protection using a high-yielC inx (e.g., iTraxx Crossover) ansell protection using investment-gra C inx (e.g., iTraxx Main). long bon卖保险没有理解这个逻辑
NO.PZ201712110200000507 问题如下 Baseon the three economic outlook statements, a profitable long/short tra woulto: A.sell protection using a CanaC IG anbuy protection using a US C IG. B.buy protection using iTraxx Crossover ansell protection using iTraxx Main. C.buy protection using electric cC ansell protection using a trationcC. B is correct.Baseon Outlook 1, ChanSmith anticipate thEurope’s economy will weaken. In orr to profit from this forecast, one woulbuy protection using a high-yielC inx (e.g., iTraxx Crossover) ansell protection using investment-gra C inx (e.g., iTraxx Main). iTraxx Crossover iTraxx Main在题目中哪里提到了好债券还是差债券
NO.PZ201712110200000507 老师，没太理解这里的long short如何带来收益 A，按解析是错误的，那正确的应该是short CanaC, long US C. 我理解的是，Cana经济相对US更差，那CanaC的sprea该更大，那如果买C就需要pay更多的钱，相对卖US的C只能receive更少的钱。 这样的long/short如何带来收益呢？
NO.PZ201712110200000507 所以考试中c出现short和long 全都相应理解为short 为买保险，long为卖保险？
请问老师这个main和cross的概念在讲义中哪页呢？我怎么一点印象都没有。。
